The surfaces that can be cleaned with commercial jet washing

Concrete forecourts and car parks

The most common commercial surface and one that handles high-pressure cleaning well. Dense concrete can take 2,500 to 3,500 PSI with a 25-degree nozzle or surface cleaner attachment. Pre-treat oil stains and fuel contamination with an industrial alkaline degreaser before washing. Hot water produces significantly better results on oil-contaminated concrete than cold water. Always start at the highest point of the forecourt to direct dirty water towards the drain.

Tarmac and asphalt surfaces

Tarmac is softer than concrete and requires lower operating pressure, typically 1,200 to 1,800 PSI. High pressure on older or deteriorating tarmac will lift aggregate from the binder, causing surface damage that is expensive to repair. Use a wide fan nozzle or surface cleaner attachment. Avoid hot water at high temperatures on tarmac as heat can soften the binder. For oil staining, a cold-water alkaline pre-treatment is preferred over hot water pressure washing on asphalt surfaces.

Block paving and paved pedestrian areas

Block paving on commercial premises receives intense use from foot traffic, delivery vehicles and plant equipment, generating heavy contamination in the joints as well as on the surface. Pressure wash diagonally across the joints at medium pressure using a surface cleaner where possible. Always re-sand the joints with kiln-dried sand after pressure washing commercial block paving as the high volumes of water involved remove more sand than typical residential cleaning.

Render and external wall finishes

Render and external wall finishes are significantly more susceptible to damage from high-pressure washing than concrete floors. Roughcast, pebble dash and traditional sand and cement render will be damaged by the pressures appropriate for forecourt cleaning. Use a low-pressure softwash approach with biocidal treatment for render surfaces, particularly for algae and biological growth. Modern acrylic render systems should be cleaned with the softwash or DOFF steam method only. Direct high-pressure water at render can cause cracking, blowing and water ingress behind the coating.

External brickwork on commercial buildings

The same principles that apply to residential brickwork apply to commercial brickwork. Modern dense brick handles medium-pressure washing. Victorian and heritage brick requires low-pressure or DOFF steam cleaning to protect the fire skin and lime mortar. Commercial buildings in London often mix brick types and construction periods across a single facade, making surface-by-surface assessment essential before any programme of facade cleaning begins.

Metal cladding, shutters and roller doors

Powder-coated and painted metal surfaces respond well to TFR pre-treatment and medium-pressure rinsing. The main risks are forcing water into electrical conduits and motor housings on electric shutters, and directing pressure at any point where panels overlap, which can drive water behind the cladding. Work at 40 degrees angle to metal surfaces and avoid directing the jet at joints, seals or any electrical components. Stainless steel surfaces respond to specialist stainless steel cleaner applied before pressure rinsing.

Commercial vehicles and fleet

Commercial vehicles parked at business premises can be included in a site cleaning programme. TFR pre-treatment is applied from bottom to top of the vehicle using a foam lance, allowed to dwell for 3 to 5 minutes and rinsed top to bottom. Particular attention to wheel arches, sills and the undercarriage removes the road salt and brake dust accumulation that causes accelerated corrosion. Vinyl livery requires pH-neutral products at lower pressure rather than standard alkaline TFR at full concentration.

Related articles